It is well known in the art to solder electronic package receiving sockets to circuit boards, particularly to meet military and aircraft manufacturers' requirements. In those cases where sockets have solder tail leads which are received and soldered in holes in the board, soldering processes are generally well defined. Soldering sockets having solder feet to conductive pads on a circuit board; i.e., surface mount soldering, is, on the other hand, susceptible to failures due principally to faulty preparation prior to soldering which leads to cracks and at times total breakage at the solder joint. Generally, the faulty preparation arises from solder feet on the contact elements not being completely in contact with the solder paste because of accumulative tolerance conditions in manufacturing the contact elements and socket housings, circuit board bowing and solder paste deposition. Sockets having solder feet along the edges and projecting outwardly can be visually inspected just prior to soldering as well as afterwards to detect such problems. However, sockets having an array of solder feet both along the edge and interiorly; e.g., pin grid array sockets, are not susceptible to visual inspection and accordingly surface mounting of these type sockets has been troublesome. Further, the problems are not minor when a large number of contact elements are involved. Currently, 324 contact elements are now common in pin grid array (PGA) sockets and it is expected that the number will reach 1000 in the near future.
One approach to solving these problems would be to remove the housing on a PGA socket to visually inspect the positioning of the solder feet in the solder paste before soldering. However, removing the housing would actually aggravate the problems through inadvertent dislodging of the contact elements.
A solution to the aforementioned problems would be the use of an application tool removably mounted on the socket and having pins which enter the socket and push on the contact elements to simultaneously and uniformly seat the solder feet into the solder paste.